Over the past few years, acclaimed experimental rapper Danny Brown has been teasing an album marking his 40th birthday, as he did in 2011 with his album “XXX” after he turned 30. On Friday, Brown delivered on his promise and released “Quaranta” (Italian for 40), featuring a seemingly dreary portrait of Brown on the cover, suggesting a more mellow body of work.

While “XXX” is defined by its chaotic, borderline-industrial production and frantic rapping from Brown, “Quaranta” is the opposite side of the coin sonically, for the most part.

Brown uses his signature nasally rapping voice for much of the album, yet most of the production is smooth and atmospheric as opposed to abrasive. However, that does not mean it is not experimental. Brown is still as creative as ever and pushes the rap genre forward on “Quaranta.”

Setting a dark, atmospheric tone for the album, the title track “Quaranta” eases the listener into Brown’s introspective but brief (just 34 minutes in length) body of work.

“A lot changed since XXX came out. Bought a few cars and a house. Almost had a spouse, got caught up, she was out. Now I’m sitting here, questioning what life is about,” Brown said on “Quaranta.”

The track works as an album opener in two ways. It sets a reasonable expectation for what the majority of the following tracks will sound like (sonically, this is not “XXX” — Brown is a different person, and naturally his music is different, too). Additionally, the opening track intentionally subverts the listener’s expectations as Brown sweeps the rug out from underneath you with the very next track, the album’s lead single “Tantor.”

Even on a quieter album, at least when compared to Brown’s other acclaimed works like “XXX” and “Atrocity Exhibition,” he still manages to keep it interesting.

Produced by the ever-prolific and collaborative The Alchemist, the track is one of the more intense tunes on the album. “Tantor” starts with rock drums and a distorted horn melody as Brown effortlessly rides the odd, cycling beat. The song’s beat is perfectly abstract, something Brown has perfected over the years. It is a highlight of the album, despite being the shortest track.

The third track, “Ain’t My Concern,” is the most atmospheric song on the album as it is dominated by a ‘90s trip-hop drum cycle complimented by some echoey jazz keyboard chords. Brown, again, flows over the abstract-sounding instrumental, perfectly matching the emotion of each intricate chord.

Fifth on the tracklist, “Y.B.P.” (an acronym for young, Black and poor), is the greatest and catchiest song on the album. The looping hummed melody in the background is both ominous and ear-wormy, and the percussion loop is simple yet effective. The track features a verse from Detroit rapper Bruiser Wolf who delivers his bars with an animated vocal cadence and caps off the feature with a memorable quip about OJ Simpson: “My city show no love. It’s hard to fit in the murder mitten like OJ glove.”

Also up there with the best on “Quaranta” is the song “Down Wit It,” which features a triumphant, epic bass line backed with distant reverberated synth pads culminating in an ambient soundscape in the chorus. This track shows, again, that Brown can put out avant-garde ragers and vibe-y tracks to play on a night drive on the same album and make it work.

The album as a whole is incredibly sonically cohesive. The record is a musical rollercoaster that drifts into cold-dreary instrumentation more often than not, yet is not collectively musically depressing as the album cover would suggest.

Following the ambient vibe of “Down Wit It,” the song “Celibate” gets even quieter with Brown showing off his knack for clever wordplay: “I used to sell a bit. But I don’t f— around no more, I’m celibate. Had me trapped in that cell a bit.”

At 42 years old, Danny Brown has once again released a prolific record. Concise in its length yet dynamic in the energy it displays, Brown has further proved that he can make singular, vital music, even if it does not carry the same crazed energy as some of his earlier work.